Various apparatuses and methods have been developed for providing viewers of broadcast and cable television weather presentations with informative and accurate weather information. Typically, such apparatuses provide a display of representations of weather phenomena, e.g., clouds, rain, storms, etc., overlaid on a map of a geographical area of interest. Such displays were originally created by drawing representations of weather phenomena, or placing pre-made weather phenomenon symbols, on a physical map of an area of interest. The image of the map was then broadcast to viewers, usually with a weather presenter positioned in front of the map to provide an explanation of the map display. Computer apparatuses now are employed to facilitate the generation of weather report displays, using computer-generated graphics and animation.
A typical computer-implemented apparatus for preparing a weather presentation will include detailed digital maps of geographic areas of interest stored for access by the computer. Weather information, such as satellite imagery and/or weather radar information, such as NEXRAD weather radar information provided by the government or live local radar data, is provided to the apparatus. The apparatus scales the received weather information, which is then overlaid on the digital maps to create a graphic display of the weather for a particular area of interest. Weather information received by the apparatus may be processed to generate weather symbols, color contours, or other representations of the weather information that are overlaid on the digital maps to create the weather display. A series of such weather displays may be generated by the computer apparatus, and played back in sequence to provide an animated image of the movement of weather phenomena through a geographic area. Such apparatuses may provide an operator with various tools for selecting, e.g., the geographic location to be displayed, reference points to be displayed on the geographic map, e.g., cities, roads, borders, etc., the source of the weather information to be displayed on the geographic map, e.g., satellite imagery or radar, and how the weather information will be represented, e.g., symbols, color contours, etc. Weather forecast displays are generated in a similar manner using weather forecast information obtained from various sources, such as, for example, weather forecast models.
Using an apparatus as described above, a series of scenes may be generated that are combined to form a complete weather report presentation of past, present, and/or future weather conditions for one or more geographic areas of interest to the viewers thereof. Typically at least a portion of such a weather presentation, i.e., at least some of the computer generated scenes forming the presentation, are presented to viewers by an on-screen weather presenter who appears in front of or as part of the computer generated scene while explaining the information presented therein. This effect is achieved by positioning the weather presenter in front of a background screen of a particular background color, e.g., typically a green or blue screen. A camera captures the image of the presenter in front of the screen and provides that image to a computer which replaces each picture element (pixel) in the camera image having the background screen color with a corresponding pixel from the computer generated weather presentation scene. Thus, the weather presenter appears in the computer generated scene in the weather report presentation. This combined scene, with the weather presenter appearing in the computer generated scene, is provided on a monitor that is visible to the presenter so that the presenter can coordinate his or her position and movements in real space with the computer generated scene, e.g., to point out to viewers specific areas of interest in the computer generated scene.
In some more advanced weather report presentation apparatuses of this type the on-screen weather presenter is able to interact with the computer generated scene in which the presenter appears. For example, in such apparatuses, by movement of the presenter's hand or other part of the body, or of a pointing device held by the presenter, the presenter may draw lines, cause computer generated objects to appear or disappear, and/or move such objects around on the computer generated scene in which the presenter appears. This effect may be achieved by analyzing the image obtained by the camera of the presenter in front of the background screen to find and track the position of a pointing element, e.g., the presenter's hand, in the field of view of the camera. Exemplary apparatuses and methods for tracking a pointing element in a video field in this manner are described, for example, in U.S. Pat. Nos. 5,270,820, 5,699,442, and 6,549,659.
Using the above apparatus and method, the particular dimensions and location of the background screen are usually known and recorded, such that the location of the pointing element within the background screen can be determined. Alternatively, the background screen may be used in a carefully controlled environment where the exact location and orientation of the background screen may be easily determined based on the color used in the background screen. The orientation and/or shape of the background screen to be used in such a location may vary significantly making location of the pointing element more difficult.
Recent trends in weather presentation have introduced “on scene” weather reporting where the weather presenter makes their presentation from a location of interest, such as in a backyard setting, at a picturesque location, near where a hurricane will make landfall, etc. Providing the weather presentation in such a location is difficult given that precise determination of the boundaries, orientation, and location of a background screen, and a pointing element located therein, is difficult. Determining the boundaries and orientation of the background screen may further be difficult since the likelihood that colors that are the same as the background screen will exist in one or more non-studio locations screen is not likely.
Yet further, during an “on scene” weather report, it may be desirable to use a unconventional surface as a background screen. An example may be the side of a weather reporting van, the wall of a building, etc. The dimensions and orientation of such a background screen may be highly variable dependent on the location of interest and the size, lighting, and orientation of the unconventional surface being utilized.
What is desired is an apparatus and method for the determining the location of a pointing element in a cropped video field. What is further desired is such an apparatus and method configured to determine the boundaries of the cropped video field independent of the size and orientation of the surface providing the cropped video field.